What is tubulin polymerization?

Tubulin dimers polymerize to form microtubules, which generally consist of 13 linear protofilaments assembled around a hollow core (Figure 11.37). The protofilaments, which are composed of head-to-tail arrays of tubulin dimers, are arranged in parallel.

What is required for polymerization of microtubules?

They are formed by the polymerization of a dimer of two globular proteins, alpha and beta tubulin into protofilaments that can then associate laterally to form a hollow tube, the microtubule. The most common form of a microtubule consists of 13 protofilaments in the tubular arrangement.

What happens during microtubule polymerization?

Polymerization dynamics allow microtubules to adopt spatial arrangements that can change rapidly in response to cellular needs and, in some cases, to perform mechanical work. Microtubules utilize the energy of GTP hydrolysis to fuel a unique polymerization mechanism termed dynamic instability.

What causes microtubules to depolymerize?

The tubulin subunits near the ends of rapidly growing microtubules are more likely to be bound to GTP (Figure 1D), and the loss of the GTP–tubulin portion, known as the GTP-cap, renders the microtubules more prone to depolymerization (Figure 1E).

What is tubulin polymerization assay?

Tubulin polymerization assay (BK006P) is based on an adaptation of the original method of Shelanski et al. and Lee et al. (1, 2) which demonstrated that light is scattered by microtubules to an extent that is proportional to the concentration of microtubule polymer.

Why is microtubule polymerization important?

Main Text. Microtubules are essential players in the function of the cell. Together with actin filaments and intermediate filaments, they comprise the cytoskeleton in eukaryotic cells, and this group of polymers is collectively responsible for providing most of the structure and spatial organization in the cell.

What is polymerization assay?

It is an adaptation of an assay originally described by Bonne, D. et al. (1). Polymerization is followed by fluorescence enhancement due to the incorporation of a fluorescent reporter into microtubules as polymerization occurs. The standard assay uses neuronal tubulin (Cat.

What are tubulin binding agents?

Most tubulin-binding agents (TBAs) act on spindle microtubule dynamics, which are important for normal spindle function (reviewed in Ref. 6). Disruption of spindle microtubules results in mitotic arrest, which can lead to cell death through various mechanisms. DNA is shown in blue.

Which drug inhibit the polymerization of tubulin?

One class of inhibitors operate by inhibiting polymerization of tubulin to form microtubules and are called polymerization inhibitors like the colchicine analogues and the vinca alkaloids. They decrease the microtubule polymer mass in the cells at high concentration and act as microtubule-destabilizing agents.

How does colchicine inhibit microtubule polymerization?

Colchicine is a classical anti-mitotic drug which blocks mitotic cells in metaphase. It binds to soluble tubulin to form tubulin-colchicine complexes in a poorly reversible manner, which then binds to the ends of microtubules to prevent the elongation of the microtubule polymer.

Is tubulin a receptor?

Tubulin promotes receptor-independent activation of G proteins. Heterotrimeric G proteins promote tubulin GTPase, increasing microtubule dynamics. GPCR activation releases Gα and Gβγ from plasma membrane, modifying cell morphology.